Apparatus for cementing wells



Nov. 9 1926. 1,606,606

w. T. THOMAS APPARATUS FOR CEMENTING WELLS Filed June a, i926 31a/vanto@T/zvmas 'ibatenteld Novo 9 i226.,

intere rarer-rr entre WELLM T. THOMXS, OFIWXCHITA FALLS, TEMS, ASSIGNOROli? ONE-HALF T AMERI- UAN lEtN @L MACHINE WORKS, m0., @3F TONKAWA,KLAHOM., A CRPQMTIUN or ontsporen.

application med June t,

This invention relates to apparatus lfor cementing wells and moreparticularly to an improvement of that type of cementing apparatusillustrated in my prior patent, No.

e 1,576,074, granted March 9, 1926, for apparatus for sealing oil wells.

An important object of the present invention is to provide aconstruction such that improper location of the cement charge which isbeing placed in the well is 'absolutely avoided. ln cementing wells bythe process employed in the patent above referred to and by similarprocesses, the cement charge is placed within' the casing. Upon this l5charge is placed a plug, the function of which is to maintain the chargein position after it has been forced into such position by hydraulicpressure applied through a pump connected with the casin at the u perend thereof. These plugs, i they fit t e casing, often seal above thecement an air pocket, the length of which causes a correspondingdisplacement of the cement charge,

so that it is improperly spaced. Furthermore, the upper surface of thecement mingles with the hydraulic charge, so that the cement is renderedextremely soup and instable, so that it requires a relatively long timefor 'the cement tol set and ad]acentthey lower end of the casing, intowhich the cement tends to return, there is often a pocket vin which thequality of the cement is so poor that a proper setting thereof is noteffected by the time the drilling is begun. In ac- 'cordance with thepresent invention, means `are provided to prevent the formation of anair pocket and to permit -the cement to return to a predetermined leveland by its own pressure drive therefrom any excess fluid which wouldtend to cause improper setting thereof.

Furthermore, in setting cement in oil wells vby the process set forth inmy`^ prior patent, the arrival of the plug at .the pro er point in thecasing is determined by the act that since no further duid can flow intothe casing, the hydraulic pressure employed for driving` theplug andcement downwardly builds up'relat-ively rapidly. The lug once inposition is locked in this osition, so that it cannot return andprovides aperpetual seal, so that when the pump pressure is re-APPARATUS EUR CEMENTEE@ WELLS.

1.926. Serial No. 114,492.

moved, there is no tendency to back-How of the fluid employed inproviding the pressure against the cement. A further and importantobject of this invention is to provide a device of this character which,while giving the indication of the arrival of the plug at the properposition in the same manner as in' my prior patent, permits the lug toshlft after it is engaged .with its seat through a vpredetermineddistance, which opens a number of minute openings through which watermay pass but in which the cement has a tendency'to clog.

ceI

These and other objects I attain by the-"- Figure 3 is an enlargeddetail sectionalA view through the disk showing the Amanner 3flrr'egulating the size of the; openings of the lReferring now moreparticularly to the drawings, the numeral 10 generally designates acasing of a well bore ll-which is to be cemented and 12 indicates a shoeof the casing which is disposed at the lower end thereof. In accordingwith my invention,

a disk 13 is placed Within the casing adjacent the shoe 12' and ispreferably held in position by a coupling 14 connecting the shoe withthe lower end of the casing. This disk has a central opening 15 in thelower end of a depending neck 16, the upper sur'- face of the connectionof the neck withth disk roviding a valve seat 17'. I

llhls disk is formed with a plurality of minute openings`18 which mayhave any. suitable arrangement and a number of which areformed. in,theneck 16 of-the disk. Theseopenings are preferably about one sixty-fourthof anv inch in diameter.

' no part of my invention.

The plug employed consists of a cylindrical body 20 of less diameterthan the interior diameter of the casing in which it is to be employedand is formed at its lower end with a head 21 having a neck 22 of a sizeto extend through the neck 16 of the disk 13 and the opening 15 thereof.The

lower endA of the neck 22 has an openlng 23 in opposition to which isarranged an upwardly cupped washer element 24 formed of flexiblematerial. This washer element is supported by a rod 25 threaded in theupper head 26 of the plug and extending "through the neck 22 of thelower head 21 thereof. The lower end of the rod has a head 27 andbetween this head and the washer a spring 28 is disposed which normallyurges the washer upwardly for engagement with and sealing of the opening23 of the neck.l Both the upper and lower heads of the plug may beprovided with 'a series of small openings 29, if so desired.

The exterior of the plug adjacent its upper end has preferably securedthereto an annular bristle clump 30, the bristles o f which arerelatively sti and engage against the walls of the casing. Thesebristles serve to brush from the walls of the casing any cement whichhas a tendency to adhere thereto, so that' this cement will not dry u onthe walls of the casing and afterwards uring the drilling operationflake 0E.

The method of employing the apparatus is as follows: The disk 13 havingbeen positioned and cemer admitted to the well, the plug is dropped in otop ofthe cement and hydraulic pressure applied to the well to force thecement to its position between the wall ot the bore 11 and the casing.When the plug comes into contact with the disk, the washer 24 will passbelow the disk and the plu will come into sealing engagement with t eseat 17. 'Ihe sudden rise in pressure will advise the operator of thepump that the plug is in engagement with the disk and 'pressure is shut0E and the well opened. he cement will then tend to return to the casingand the Huid on top of the cement will be forced through the openings 18and thus permitted to escape from the cement. The cement coming intocontact with these openings will seal the same, preventing loss of anyappreciable quantity of the cement. At the same time, liquid or air maymove through the interstices `of the cement particles to the openingsand thus escape.

It isv pointed out that at this time, the plug'20 may move upwardly sothat this plug does not seal the openings 18, washer 24 coming intoengagement with the lower end of the yoke 25 and providing a seal forthe large opening 15 of the disk 13 while at the same time limitingupward movement of the plug. While the plug 20 will not seal all oftheopenings 18, when seated thereagainst, it is advisable that thisplug4 be permitted to move upwardly, as otherwise a complete separationof the water and cement is difcult to obtain. These openings 18 will, ofcourse, permit the passage not only of water but any other trapped Huid,suchv as air.

Since the construction hereinbfefore set forth is obviously capable of acertain range of change and modification without matcf rially departingfrom the spirit of lthe invention, I do not limit myself to such spe- Aciic structure except as hereinafter claimed.

1. Inljcementing apparatus for oil wells, a disk adapted to be securedwithin the lower end of the well casing and having a large openingformed therein, a series of minute openings likewise formed inI the diskand a plug adapted to be placed upon the cement within the well and toengage with the disk to seal the large opening of the disk and lock theplugto the'disk.

2. In cementing apparatus for oil wells, a disk adapted to be securedwithin the lower end ofthe well casing and having a large openingformedvtherein, a series of minute openings likewise formed in the diskand a hollow plug adapted to be placed upon the cement Within the welland to engage with the disk to seal the large opening of the disk andlock the plug to the disk, said. plug being formed in its upper andlower ends with a series of minute openings.

3. In .cementing apparatus for oil wells,

a disk adapted to be'secured within the lower end of the well casing andhaving a large opening formed therein, a series of minute openingslikewise formed in the disk andv a plug adapted t0 bepplaced uponthecement wlthin the well having at its lower end means adapted -to passthrough the openingoi' the disk when the plug comes into contact withthe disk and to seal the disk at the unv der surface thereof.

4. In cementing apparatus for oil wells, a disk adapted to be securedwithin the lower end of the well `casing and having formed therein anopening for the passage of cement and other openings permitting thepassage of Huid but preventlng the passage of ce,y

Lucano@ ment and a plu adapted to be placed upon the cement and avingengagement with the disk sealing the first named opening.

5. In cementing apparatus for oil Wells, a disk adapted to be securedWithin the lower end of the Well casing and having formed therein anopening for the passage of cement and other openings permitting thepassage of fluid but preventing the passage of cement and a plug adaptedto be placed upon the cement and having engagement withl the disksealing the first named opening and locking the plug to the disk.

6. A plug for use in cementing oil wells adapted to be placed upon thetop of the 'cement Within the Well, said plug being of less diameterthan the internal diameter of the casing and having projecting outwardlytherefrom a circumferential bristle clump the bristles of Which areadapted to engage against the interior Walls of the casing to removeadhering cement therefrom.

ln testimony whereof I hereunto affix my signature.

WILLIAM T. THOMAS.

